Even though concrete is the world’s most highly used construction material, scientists have failed to understand very important fundamental aspect of the material, until now.
A group of researchers from MIT, Georgetown, and CNRS in France believe they have finally figured out whether or not concrete is actually a solid, continuous material, like stone, or a group of materials that are packed so tightly together that they only act like a continuous material. The team found that although there is always a smaller particle that fills open space in the concrete (which would make it a continuous material), concrete never really stops moving, which is why it’s susceptible to cracking and degrading.
So what’s the big deal about a bunch of science junkies looking at concrete through some microscopes and figuring this out? This research could lead to better, more environmentally stable concrete. Because concrete is so widely used and it takes so much heat to cook limestone for cement mixtures, it is the world’s largest producer of greenhouse gases. Optimizing the cement mixture makeup to coincide with this new research data could not only reduce the amount of heat necessary, it could also lower the amount of water needed.
Speaking of water, it’s been widely accepted that the freeze-thaw cycle of water inside the concrete causes cracking as the water expands, but the team says that’s not actually the case. Water can actually enter through pores which range in size from 15 to 20 nanometers (read: super small, one nanometer is one-billionth of a meter) and the water alone causes cracks and further concrete degradation without the help of freezing.
Full story: Riddle of cement’s structure is finally solved | MIT
The USGBC recently released their 2017 data for the Top 10 US States for LEED construction, which is sorted by Gross Square Footage per Capita. That ranking system allows them to get a fair comparison of states, despite differences in population and number of buildings.
As the world not only becomes more familiar with green products, but also starts demanding them, researchers and contractors alike need to be ready to embrace the ever-changing world and meet their customer’s demands. Each year, new products are released that hoping to reduce waste or harness renewable energy sources, but only some of them reach the mass market.
Below are 8 green products, processes, and stories that we found most interesting in 2017:
Wood construction has typically been used for purely residential products in the past few decades and especially after fire protection standards became more stringent. Besides fire rating, concrete and metal has several other benefits over wood, including overall strength, resistance to insects, and resistance to rot. Wood, however, does have some advantages over concrete and steel, like its relative light weight and it’s much less harmful to the environment.
The Netherlands has a ton of bridges, especially pedestrian and biking bridges, thanks to its abundant system of canals. Perhaps because of that, they have become a leader in 3D printing technology when it comes to bridges.
Concrete is an extremely strong building material, but has a notoriously weak tensile strength. In order to resist tension, bending, and shear forces, steel rebar or other reinforcement materials are added either prior to the placement or into the mix. Even with reinforcement, concrete is still extremely rigid and prone to cracking. In the event of a major earthquake, the uneven and horizontal forces can cause structures to crack and, in the worst case, cause failure.
Concrete can adapt to any shape its formwork calls for while it’s being placed. While it’s POSSIBLE to make intricate designs with the material, it’s not always easy or practical to do so. Researchers from ETH Zurich have designed a new method of forming and placing an ultra-thin, curved concrete roof system that they plan on installing on a construction project next year.
As electric vehicles are becoming more and more popular around the world, researchers are trying to find ways to adapt the technology to heavier duty applications. Due to the large size of projects and amount of money in the industry, the mining industry has seen its fair share of technological advancement. Several manufacturers, like Komatsu, have developed and released driverless dump trucks for mining operations in the past few years. A team of companies in Switzerland is now working on a gigantic battery powered dump truck that will be tested for 10 years.
Rapid growth and the industrialization are the major contributors to China’s noted air quality issues. 4 years ago, the Chinese government issued a “war on pollution” aiming to improve air quality and reduce other environmental hazards, such as land and water contamination. Air quality is at its worst in the winter months across the country, due to households relying more on coal power to heat residents’ homes.
Asphalt is one of the world’s most popular pavement materials. Because of that, researchers and scientists are constantly looking for ways to improve upon it. Additives have been included in some asphalt mixes for years to improve strength, but recently researchers have been getting pretty clever with the types of additives they’re testing.
As great as a product as asphalt is, there’s no doubt that there is room for improvement. Scientists all over the world are trying to solve its most common issues, such as potholes, cracking, ice build-up, and storm water drainage. Los Angeles is now tackling another issue with the material: heat island effect.